I did the first two parts (a-b), but I'm stuck on c,d & e, the questions about the Energy of the spring.

2. Relevant equations

PE = .5kx^2

and

KE = .5KA^2

F/x=k

3. The attempt at a solution

I've tried these 3 multiple times and I keep getting them wrong. One thing I'm not sure of, is is "x" the amplitude? I have been plugging in .29 for the "x" and .47 for the "A", but just curious if this is the reason I'm getting these wrong.

I would think, that according to these formulas, KE+PE=TOTAL ENERGY, and I thought I was doing them right. I'm at my wits end.

I don't know why you're using the amplitude to find the value of k, use [tex]\omega[/tex] and the mass to find the value of k as shown in the equation above. The spring does not stretch to its amplitude at equilibrium, nor does it stretch to the value of x the question gives you.

Thanks, you were SO helpful!! I didn't realize that you can't always use the equation of F=-kx to find k!

I'm really thankful and grateful that you stayed online and helped me through each step. Thanks again, you're a really good person. =)

You can always use F=-k x at two conditions: that the F you use is the force exerted by the spring and that the x you use is the displacement of the mass from the equilibrium position. I am not sure why you concluded that you can't always use that equation but I wanted to point that out.